Epilepsy is a chronic illness caused by abnormality in the central nervous system. An epileptic seizure is a brief, excessive surge of electrical activity in the brain that causes a change in consciousness, sensation and behavior. During an epileptic seizure, the regulatory systems that maintain the normal balance between excitation and inhibition of the brain's electrical activity break down. There may be a loss of inhibitory nerve cells or an overproduction of an excitatory neurotransmitter. Groups of abnormal cells are activated synchronously, creating a storm of electrical activity.
Patients taking anticonvulsant drugs display a broad spectrum of side-effects. The widely used drug carbamazepine, shows side effects such as dizziness, ataxia, drowsiness and reduction of alertness. See, A. Delcker et al., Eur. Neuropsychopharmacold., 7, pp. 213-8 (1997). Valproic acid may precipitate metabolic disorders, liver disease, gastrointestinal symptomatology, excessive bodyweight gain and alopecia. See, S. J. Wallace, Drug Saf, 15, pp. 378-93 (1996). Barbiturates precipitates metabolic bone disease and rash. See, S. J. Wallace, Drug Saf, 15, pp. 378-93 (1996). Therefore, there is a need on the market for anticonvulsant medication with fewer side effects.